Manufacture and use of agricultural spray adjuvants for hard water conditions

ABSTRACT

The invention pertains to a method for manufacture and use of pesticides or agricultural spray adjuvants that counteracts the effects of hard water cat ions on anionic pesticides when applied in water spray solutions. The disclosed agricultural spray adjuvants include glyphosate compositions comprising a strong mineral acid, such as sulfuric acid, and a polyamine surfactant, such as tallow amine or coco amine.

RELATED APPLICATIONS

This application is a continuation of U.S. application Ser. No.10/853,781, filed May 26, 2004, which issued as U.S. Pat. No. 9,668,471,on Jun. 6, 2017, which claims the benefit of U.S. ProvisionalApplication Ser. No. 60/473,540, filed May 28, 2003, each of which isincorporated herein by reference in its entirety.

BACKGROUND

It is known that the addition of fertilizer blends in the application ofmany pesticides will improve the performance of the active ingredient.The current market standard is ammonium sulfate (AMS). It is speculatedthat one of the reasons for this is that the anion portion of thefertilizer blend, sulfate, will associate with the hard water cation.Therefore the anion or acidic pesticide will not associate with the hardwater cation and be more available for uptake into the target species.“Data suggest hard-water cations, such as Ca⁺² and Mg⁺² present in thespray solution can greatly reduce the efficacy of glyphosate. Thesecations potentially compete with the isopropylamine in the formulationfor association with the glyphosate anion.”¹ Hard water with cationspresent in a concentration range higher than 100 ppm-150 ppm have beenshown to cause a decrease in effectiveness of many pesticides.² It isthought by some authors that the reason for the reduced activity withglyphosate is that the glyphosate anion will form insoluble salts withmany hard water cations. This would be true for many anions pesticidesincluding glyphosate, 2,4-D and glufosinate. This would also be true foracidic herbicides that could become anionic depending upon pH an exampleof this would be sethoxydim.^(3,4)

This information has lead to the common practice of glyphosate and otheranionic pesticides being applied in the presence of ammonium sulfate(AMS) in the spray mixture. However, in other industries a commonpractice to remove hard water cations such as Ca⁺², Fe⁺², Mg⁺² and Zn⁺²is with acidic reaction with mineral acids such as nitric and sulfuricacid.⁵ This technology has been adapted to cation management in bothsoil and irrigation water and is based on the “Langelier index”.⁶ Cationmanagement with phosphoric acid as a spray mixture has been tried withlimited success as compared to spray mixtures containing AMS. It isspeculated that the reason that phosphoric acid products do not work aswell as AMS is that phosphoric acid does not completely dissociate whenadded to water at normal spray mixture pH ranges.⁸ It is therefore lessreactive to the hard water cations than originally thought by thecreators of these products. Other mineral acids were considered to beimpractical in pesticide applications because small mistakes or misusewith these powerful acids will drop the pH of a spray solution in thespray tank below the pKa of many anionic pesticides, includingglyphosate. If this occurs the pesticide will precipitate and will nolonger be sprayable.

An idea was formed that mineral acid management of hard water cationswould be much more efficient than AMS management of hard water cationsif a mineral acid that completely dissociates in water could be used anda reliable delivery system could be devised or discovered for thesetypes of acids. The three driving factors for this idea are: 1) Muchless acid is needed to tie up the hard water cations than AMS. Theamount of AMS recommended is 17.5 lb per 100 gallons of waters with150-250 ppm hard water cations. ⁴ Whereas only 1.3 oz of sulfuric acidper 100 gallons is needed to neutralize the 150-250 ppm hard watercations.⁷ 2) Sulfuric acid and nitric acid will form semi and insolublesalts with the hard water cations. Whereas AMS has only been shown toassociate with these cations. It is unlikely that they form salts.³ 3)AMS as a salt is hard to dissolve into the spray solutions which makesit difficult to work with. Whereas, acids are completely miscible inwater.

1. The basis for the hard-water antagonism of glyphosate activity.Thelen, K. D. Weed Science v. 43 (4) 1995 pp. 541-548.

2. Weed Science Principles and Application. Anderson, WP third edition,West Publishing Co. Minneapolis, Minn.

3. Nalewaja, J. D. and R. Matysiak. 1993. Pesticide Sci. 38:77-84.

4. Role of AMS with glyphosate products. Hartzler, R. ExtensionBulletin, Iowa State University.

5. David Wm. Reed. 1996. Water, media and nutrition for greenhousecrops. Ball Publishing, Batavia, Ill., ISBN: 1-883052-12-2.

6. Bohn H. L., McNeal, B. L., O'Connor, G. A., Soil Chemistry, AWiley-Interscience Pub. John Wiley & Sons, New York, N.Y.

7. Greenhouse Product News February '99.

8. Morrison R. T. and Boyd N. B. Organic Chemistry, Allyn and Bacon,Boston, Mass.

SUMMARY OF THE INVENTION

A mixture of strong mineral acids which would completely dissociate inwater, including but not limited to; nitric acid, hydrochloric acid,sulfuric acid, perchloric acid, and a polymer, preferred would becationic, that is formulated as an agricultural spray adjuvant. Thepolymer in the formulation acts as a slow release mechanism for theacid. Polymeric forces on the mineral acid give the grower a practicalmechanism for using mineral acid to counteract hard water cations. Theadjuvant when mixed in a agricultural spray solution would act to tie upthe hard water cations thus protecting any anionic pesticides,defoliants or plant growth regulators from reacting with the hard watercations such as Ca⁺⁺, Mg⁺⁺, Fe⁺⁺ and becoming less effective as anagricultural chemicals. Thus the spray adjuvant would act to increasethe apparent efficacy of the active ingredient being applied.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1. Formula 21-1 as compared to AMS for the reduction of hard watertie up of glyphosate salt. As measured by percent control of annualbluegrass. Zinc acetate added as the complexing Anion. V/v=volume tovolume.

FIG. 2. The effect of Formula 21-1 on restoring the activity ofglyphosate as demonstrated by percent control of annual bluegrass ascompared to ammonium sulfate (AMS). Magnesium Sulfant (MgSu) was addedto the mixture to simulate hard water cations.

DETAILED DESCRIPTION OF THE INVENTION

Strong mineral acids were added to polymers in an attempt to deliver acontrolled amount of acid into a spray solution. The acid would act as a“hard water cation scavenger”. The mixture would be an agronomic spray“hard water scavenger system”. In the preferred example sulfuric acidwas added to tallow amine. Heat was given off indicating some reaction.However, pH measurements of spray mixtures taken before and after theaddition of the “hard water scavenger system” shows that free acid stillexisted.

Knowing that any potential spray solution which could be contemplatedwould have to stay above a pH of which is higher than the pKa of mostanionic pesticides. Differing mixtures of several examples where madeup. Table 1, Table 2, Table 3. It was thought that this would be a moreefficient method to condition the spray waters than current practice ofusing Ammonium Sulfate (AMS). However, the mixture would have to remainstable, not drop the pH below the pKa of anionic pesticides and work aswell as or better than AMS. The efficiency would be gained by replacinglarge bags of dry AMS (17.5 lbs/100 gallons spray solution) or largevolumes (5 gallon/100 gallons spray solution) of liquid AMS with 1 quartto 1 gallon per 100 gallons of spray solution with this kind of product.Also this liquid product would go into solution much faster than thecurrent AMS goes into solution adding even more efficiency.

It was discovered that cationic macro molecules would make a stable mixwith sulfuric acid. Also, cationic surfactant would act as a system thatwould deliver enough free acid to tie up hard water cations. While atthe same time maintain the pH of the spray water above the pKa of theactive ingredient being sprayed thus increasing the efficacy of thepesticide.

It was surprising to discover that these mixtures increased ormaintained the efficacy of anionic pesticides under hard waterconditions much better than the current practice of adding AmmoniumSulfate (FIG. 1 and FIG. 2).

TABLE 1 Example 1 Formula 21-1 Water 65.9%/wt Tallow Am 3780 30.0 SAG 100.1 93% Sulfuric 4.0

TABLE 2 Example 2 Formula 21-2 Water 45.9%/wt Tallow Am 3780 50.0 SAG100.1 93% Sulfuric 4.0

TABLE 3 Example 3 INGREDIENT %/WT Diethylene Glycol 17.80 NP-10 50.00AU391 30.00 93% Sulfuric Acid 2.00 SAG 10 [ 0.20

What is claimed is:
 1. A water soluble glyphosate compositioncomprising: (a) an aqueous glyphosate solution comprising glyphosate ora salt thereof; (b) a concentrated solution comprising sulfuric acid anda polyamine surfactant selected from tallow amine ethoxylate and cocoamine ethoxylate combined in an agricultural spray solution; whereinsaid composition does not contain ammonium sulfate (AMS); and whereinsaid composition consists of a ratio of 1 quart to 2 gallons of (b) to100 gallons of (a); and wherein said composition has a pH above the PKa₂of glyphosate, and wherein better herbicidal efficacy is provided incomparison to 5-20 pounds AMS per 100 gallons of (a).
 2. The compositionas claimed in claim 1, wherein said polyamine surfactant is tallow amineethoxylate.
 3. The composition as claimed in claim 1, wherein saidpolyamine surfactant is coco amine ethoxylate.
 4. A water solubleglyphosate composition of claim 1 wherein said composition consists of aratio of 1 quart to 1 gallon of (b) to 100 gallons of (a).
 5. Thecomposition as claimed in claim 1, further comprising sodium bisulfate.